Co3O4 nanoparticles embedded in laser-induced graphene for a flexible and highly sensitive enzyme-free glucose biosensor

Developing flexible and wearable enzyme-free biosensors for detecting glucose is indispensable for preliminary diabetes diagnosis and human healthcare monitoring. Herein, an innovative flexible Co 3 O 4 nanoparticles uniformly embedded in 3D porous laser-induced graphene (Co 3 O 4 NPs-LIG) electrode is fabricated by a new one-step laser direct writing carbonization technique. The hybrid electrode featuring the remarkable synergistic effect on account of the excellently conductive LIG and multiple high activation sites of Co 3 O 4 NPs can enhance charge transfer, thereby boosting glucose sensing performance. Benefit from the dramatic properties, the proposed flexible non-enzymatic glucose biosensor exhibits a prominent glucose sensitivity of 214 μA mM –1 cm –2 , an extremely low limit of detection of 0.41 μM, a wide linear detection of 1 μM to −9 mM, and a fast response time within 0.49 s. Additionally, impressive repeatability, favorable stability, and great selectivity are achieved in the detection of glucose concentration . Finally, a possible sensing mechanism of the glucose biosensor is also discussed based on the First principles. This study provides a novel and facile strategy for constructing heterostructure of transition metal oxide NPs embedded in LIG, which serves to develop flexible and wearable highly sensitive enzyme-free biosensors for detecting glucose in the near future.